Industrial endoscope lens for micro motor stator detection and forming process

Abstract

The invention relates to the technical field of industrial endoscopes, in particular to an industrial endoscope lens for micro motor stator detection and a forming process, and the endoscope lens realizes the balance between a large field of view and high imaging quality through a specially designed lens combination. The full view field is 64 degrees, the internal area of the micro motor stator can be completely covered, and it is ensured that a detection image is clear and accurate. The endoscope lens adopts a spherical lens design, and is simple in structure and low in manufacturing cost. Due to the small size (the total length is 60mm and the caliber is smaller than 16mm), the device can go deep into the stator of the micro motor, the detection requirement of a narrow space is met, and an efficient and accurate solution is provided for industrial detection. The F number of the endoscope lens is 3.3, the entrance pupil diameter is 1.2 mm, the working distance is 20 mm, all parameters are optimized, it is ensured that high-quality images can be provided in actual detection, and therefore the problem that an existing industrial endoscope is poor in detection precision and angle is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial endoscopes, and in particular to an industrial endoscope head for micro motor stator detection and a forming process. BACKGROUND

[0002] With the vigorous development of new energy automobile and other industries, in the manufacturing, assembly and maintenance links of micro motor, iron filings, glue and other impurities are easily attached inside the stator, and cracks and scratches are easily generated on the inner wall of the aperture. The traditional detection method is mostly artificial contact type destructive detection, however, the micro motor structure is complex and difficult to be fixed and clamped by machinery, this method is easy to damage the surface of the part, even causes it to be scrapped, and brings economic loss. Although the modern industrial endoscope can observe narrow space, there are some limitations in detecting the micro motor stator with the existing industrial endoscope. On the one hand, the large field optical system has large aberration, and the subsequent image processing is complex; on the other hand, some endoscopes cannot have suitable field of view, small size and high imaging quality at the same time, and cannot accurately and efficiently detect the internal defects of the micro motor stator, which cannot meet the requirements of detection accuracy, efficiency and cost control in industrial scenes.

[0003] In order to adapt to the requirements of accurate and non-destructive detection of micro motor stator in industrial detection, a new type of industrial endoscope head and its forming process are needed. The endoscope head should have a suitable field of view, which can observe the internal situation of the motor stator as a whole, avoid distortion caused by too large field of view, and have small size to facilitate detection inside the stator, while ensuring high imaging quality to clearly present the internal defect details, provide reliable basis for product quality control, and make up for the shortcomings of existing detection technology in the application of micro motor stator detection. SUMMARY

[0004] The purpose of the present application is to provide an industrial endoscope head for micro motor stator detection and a forming process, which aims to solve the problem of detection accuracy angle of the existing industrial endoscope.

[0005] To achieve the above purpose, in a first aspect, the present application provides an industrial endoscope head for micro motor stator detection, comprising a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and an image sensor.

[0006] The first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the image sensor are arranged in order along the optical axis from the object side to the image side.

[0007] The first lens is a plano-concave lens with negative focal power, the effective focal length is-20mm, the object side is a plane, and the image side is a concave surface.

[0008] The second lens is a meniscus lens with negative focal length, the effective focal length is-27mm, the object side is concave, and the image side is convex.

[0009] The third lens and the fourth lens are both plano-convex lenses, the effective focal length of the third lens is 31.5mm, and the effective focal length of the fourth lens is 50mm, and they have positive focal length respectively.

[0010] The fifth lens is a biconvex lens with positive focal length, the effective focal length is 6.7mm, and the sixth lens is a plano-concave lens with negative focal length, the effective focal length is-38.6mm.

[0011] The fifth lens and the sixth lens are combined to form a positive cemented lens.

[0012] The second aspect is an industrial endoscope lens forming process for micro motor stator detection, which is used to prepare the industrial endoscope lens for micro motor stator detection in the first aspect, and includes the following steps:

[0013] After the preliminary processing of the raw material is performed by using the numerical control grinding machine, the fine polishing operation is performed;

[0014] The anti-reflection coating is coated on the cleaned lens;

[0015] The optical test equipment is used to detect the optical performance indexes of the lens;

[0016] The lens frame is designed and modeled, and the lens frame is printed and formed;

[0017] The lens after processing and detection is assembled into the printed lens frame in sequence to obtain a semi-finished product;

[0018] The semi-finished product is debugged and detected to obtain the industrial endoscope lens.

[0019] The industrial endoscope head for micro motor stator detection provided by the application comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and an image sensor; the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the image sensor are sequentially arranged along an optical axis from an object side to an image side. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0021] Figure 1 Fig. 1 is a structural schematic diagram of the industrial endoscope head for micro motor stator detection provided by the application.

[0022] Figure 2 Fig. 2 is an optical path diagram of the application.

[0023] Figure 3 Fig. 3 is a point column diagram of the application.

[0024] Figure 4 Fig. 4 is a field curvature and distortion diagram of the application.

[0025] Figure 5 Fig. 5 is a relative luminance curve diagram of the application.

[0026] Figure 6 Fig. 6 is an MTF curve diagram of the application.

[0027] Figure 7 Fig. 7 is an MTF curve diagram of the application at Nyquist frequency.

[0028] Figure 8 Fig. 8 is a flowchart of the forming process of the industrial endoscope head for micro motor stator detection provided by the application.

[0029] In the figure: 1-first lens, 2-second lens, 3-third lens, 4-fourth lens, 5-fifth lens, 6-sixth lens, 7-image sensor, 8-diaphragm. DETAILED DESCRIPTION

[0030] Embodiments of the present application are described below in detail, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0031] Please refer to Figures 1 to 7 , in a first aspect, the present application provides an industrial endoscope head for micro motor stator detection, comprising a first lens 1, a second lens 2, a third lens 3, a diaphragm 8, a fourth lens 4, a fifth lens 5, a sixth lens 6 and an image sensor 7.

[0032] The first lens 1, the second lens 2, the third lens 3, the diaphragm 8, the fourth lens 4, the fifth lens 5, the sixth lens 6 and the image sensor 7 are arranged in order along the optical axis from the object side to the image side.

[0033] Further, the first lens 1 is a plano-concave lens with negative focal power, the effective focal length is-20mm, the object side is a plane, and the image side is a concave surface.

[0034] Further, the second lens 2 is a meniscus lens with negative focal power, the effective focal length is-27mm, the object side is a concave surface, and the image side is a convex surface.

[0035] Further, the third lens 3 and the fourth lens 4 are both plano-convex lenses, the effective focal length of the third lens 3 is 31.5mm, and the effective focal length of the fourth lens 4 is 50mm, which have positive focal power respectively.

[0036] Further, the fifth lens 5 is a double convex lens with positive focal power, the effective focal length is 6.7mm, and the sixth lens 6 is a plano-concave lens with negative focal power, the effective focal length is-38.6mm.

[0037] Further, the fifth lens 5 and the sixth lens 6 are combined to form a positive cemented lens.

[0038] In the embodiment, in order to introduce more angle light and realize large field of view of the optical lens, the first lens 1 is designed as a negative meniscus lens. In order to extend the length of the optical imaging system, so as to be able to deeply detect the inside of the object, the second lens 2 is designed as a negative meniscus lens, which plays a role of correcting the curvature of astigmatism and central aberration. The third lens 3 and the fourth lens 4 are both plano-convex lenses, which play a role of light gathering and reducing aberration. In order to effectively correct the spherical aberration and chromatic aberration compensation, and reduce the air gap between the lenses, thereby reducing the reflection loss, improving the light transmittance, and improving the imaging quality. The fifth lens 5 and the sixth lens 6 of the application are combined to form a positive cemented lens, and the effective focal length is 16.9 mm. In order to reduce the manufacturing cost of the optical imaging system to a certain extent, all the lenses are spherical structures, and four of the six lenses contain a plane, and only one cemented lens is used. The diaphragm 8 is arranged between the third lens 3 and the fourth lens 4, and the light transmittance can be directly controlled by the size of the aperture, so that the overall imaging brightness is high and uniform. The combination of these positive and negative lenses finally realizes the optical imaging system with large field of view, small aperture, long size, and high imaging quality. The finally formed optical imaging system has a full field of view of 64°, an effective focal length of 3.99 mm, an F number of 3.3, an entrance pupil diameter of 1.2 mm, a working distance of 20 mm, and a total length of the optical system of 60 mm. The aperture is less than 16 mm. Through image simulation, the overall imaging is clear, the illumination is uniform, the distortion is small, and the imaging quality is good. Finally, the tolerance (shown in the tolerance table) analysis result shows that the system structure is reasonable and meets the production requirements.

[0039] Tolerance table

[0040]

[0041]

[0042] The specific lens data is shown in the following table. As shown in the table, the total length of the lens is 60 mm, most of the glass materials are K9, the optical glass is an optical material with excellent wide-spectrum transmittance, high hardness, and low bubble and impurity content. It can withstand various physical and chemical stimuli. All the lenses are spherical mirrors, and four of the six lenses contain a plane, and only one cemented lens is used, which greatly reduces the manufacturing cost of the lens while ensuring the imaging quality.

[0043] Lens data table

[0044]

[0045] From Figure 3It can be known that the RMS radius is 0.783 mu m at the central field of view, and the RMS radius is 1.97 mu m at the edge field of view, so the aberration of the endoscope lens has good correction, and meets the basic technical requirements of the application.

[0046] The full field of view of the application is 64 degrees, and the working distance is 20 mm. Figure 4 It can be known that the field curvature of the system is less than 0.03 mm, the field curvature is small, the distortion is greater than -20%, and the imaging effect of the system is better, which reduces the complexity of the later image processing.

[0047] The image plane of the application is uniform, the brightness is high, the F number is 3.3, the depth of field and the aperture are moderate. Figure 5 The relative illumination curve of the optical system is shown in the figure, and the relative illumination is close to 1, and the overall imaging illumination is uniform.

[0048] The image sensor 7 matched by the application is an OnSemi PYTHON300 CMOS chip, the target surface size of the sensor is one quarter of an inch, the resolution is 672512, 300,000 pixels, and the corresponding Nyquist frequency is 105 lp / mm. Figure 6 And Figure 7 The overall MTF curve and the MTF curve at the Nyquist frequency of the optical system are shown in the figures, respectively.

[0049] Please refer to Figure 8 , in the second aspect, an industrial endoscope lens forming process for micro motor stator detection is used for preparing the industrial endoscope lens for micro motor stator detection in the first aspect, and comprises the following steps:

[0050] S1 uses a numerical control grinding machine to perform preliminary machining on the raw material, and then performs fine polishing operation;

[0051] Specifically, according to the design drawing requirements, the lens raw material is fixed on the workbench of the numerical control grinding machine. The machining parameters of the grinding machine are set through programming, including cutting depth, feed speed and spindle speed. Start the numerical control grinding machine, use the diamond grinding wheel to accurately cut the raw material, gradually remove the excess material, shape the lens, and ensure that the curvature radius and thickness of the lens meet the pre-set design requirements. In the processing process, the size and shape deviation are monitored in real time, and the processing parameters are adjusted in time to ensure the processing accuracy. The lens after preliminary processing is installed on the fixture of the optical polishing machine. According to the material and surface roughness of the lens, select appropriate polishing liquid, such as aluminum oxide suspension. Turn on the optical polishing machine, and evenly apply the polishing liquid on the surface of the lens until the lens surface reaches the required smoothness and flatness.

[0052] S2 coating anti-reflection coating on the cleaned lens;

[0053] Specifically, the finished lens is placed in an ultrasonic cleaner, and an appropriate amount of optical cleaning agent is added. The cleaning time is set, usually 10-20 minutes, and the high-frequency vibration of the ultrasonic wave is used to remove oil, dust and impurities on the surface of the lens. After cleaning, the lens is rinsed with pure water to remove residual cleaning agent, and then placed in an oven for drying treatment to ensure that the lens surface is completely dry and no water stains are left. The cleaned and dried lens is installed in the coating cabin of the vacuum coating machine. Close the coating cabin door and start the vacuum pump to reduce the cabin pressure to the set vacuum degree. According to the wavelength range and design requirements of the lens, select the appropriate anti-reflection coating material, and deposit the coating material uniformly on the surface of the lens through evaporation or sputtering coating process to form an anti-reflection coating layer with a thickness of 50-100 nm.

[0054] S3 using optical testing equipment to detect the optical performance indicators of the lens;

[0055] Specifically, the optical testing equipment is accurately calibrated. The lens coated with anti-reflection coating is installed on the test stand of the optical testing equipment. According to the detection items and requirements, the optical performance indicators of the lens are detected, and the detection results are displayed in the form of data and images on the screen. The detection results are analyzed and evaluated to determine whether the optical quality of the lens meets the design requirements and use standards. If not, the lens needs to be reworked or reprocessed.

[0056] S4 design and model the lens frame, and print the lens frame;

[0057] Specifically, use 3D modeling software (such as solidworks) to open a new modeling project, and draw a three-dimensional model of the lens frame according to the overall structure requirements of the endoscope lens and the size parameters of the lens. Virtually assemble the lens model and the frame model to check for interference and assembly problems, and adjust the design parameters in time to optimize the frame structure. Start the 3D printer, and the printer will accumulate materials layer by layer according to the model data to finally print the lens frame. After printing, the formed frame is post-processed (remove support structure, polish surface, heat treatment, etc. to improve the size accuracy and surface quality of the frame.)

[0058] S5 assemble the lens after processing and detection into the printed lens frame in sequence to obtain a semi-finished product;

[0059] Specifically, the lenses and the printed lens frames that pass the processing detection are cleaned to remove dust, oil stains and other impurities on the surface, ensuring the cleanliness of the assembly environment. The appearance quality of the lenses and the frames is checked to confirm that there is no scratch, bump or other problems. According to the designed assembly sequence, the first lens is placed into the corresponding position of the lens frame using tweezers and other tools, so that it is tightly attached to the frame. Then, other lenses are sequentially assembled into the lens frame.

[0060] S6 Debugging and detection of semi-finished products to obtain industrial endoscope lens.

[0061] Specifically, the assembled endoscope lens semi-finished product is installed on the debugging device. First, the optical axis is adjusted by rotating the adjusting screw on the lens frame to make the optical axis coincide with the reference axis of the device, ensuring clear and non-offset imaging. Then, the focus is debugged by moving the position of the image sensor 7 to achieve the best clarity. After completing the debugging, the endoscope lens is comprehensively detected using the detection device. Including but not limited to imaging quality detection (resolution, distortion, color restoration, etc.), optical performance detection (transmittance, reflectance, aberration, etc.), mechanical stability detection (lens fixation firmness, frame durability, etc.), and environmental adaptability detection (performance stability under conditions such as temperature, humidity, vibration, etc.). According to the detection results, it is judged whether the various performance indicators of the endoscope lens meet the requirements of the micro motor stator detection. If all are qualified, the endoscope lens is completed and packaged and shipped; if not, it is repaired or scrapped.

[0062] The above only discloses a preferred embodiment of an industrial endoscope lens for micro motor stator detection and a forming process, of course, cannot limit the scope of the invention, those skilled in the art can understand that all or part of the above-mentioned embodiments are implemented, and equivalent changes made according to the claims of the invention still belong to the scope covered by the invention.

Claims

1. An industrial endoscope lens for micro motor stator detection, characterized in that: including a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens and an image sensor; The first lens, the second lens, the third lens, the aperture, the fourth lens, the fifth lens, the sixth lens, and the image sensor are sequentially arranged along the optical axis from the object side to the image side.

2. The industrial endoscope lens for micro motor stator inspection according to claim 1, characterized in that: The first lens is a plano-concave lens with negative optical power and an effective focal length of -20 mm. The object side surface is a flat surface and the image side surface is a concave surface.

3. The industrial endoscope lens for micro motor stator inspection according to claim 1, characterized in that: The second lens is a meniscus lens with negative optical power, an effective focal length of -27 mm, a concave object-side surface, and a convex image-side surface.

4. The industrial endoscope lens for micro motor stator inspection according to claim 1, characterized in that: The third lens and the fourth lens are both plano-convex lenses. The effective focal length of the third lens is 31.5 mm, and the effective focal length of the fourth lens is 50 mm. They each have positive optical power.

5. The industrial endoscope lens for micro motor stator inspection according to claim 1, characterized in that: The fifth lens is a biconvex lens with positive optical power and an effective focal length of 6.7 mm. The sixth lens is a plano-concave lens with negative optical power and an effective focal length of -38.6 mm.

6. The industrial endoscope lens for micro motor stator inspection according to claim 5, characterized in that: The fifth lens and the sixth lens are combined to form a positive cemented lens.

7. A molding process for an industrial endoscope lens for micro-motor stator inspection, used for preparing the industrial endoscope lens for micro-motor stator inspection according to any one of claims 1 to 6, characterized in that: The following steps are involved: Use CNC grinding machines to perform preliminary processing of raw materials and then perform fine polishing operations; Applying anti-reflective coating to the cleaned lens; Use optical testing equipment to detect the various optical performance indicators of the lens; Design and model the lens frame and print it; Assemble the processed and tested lenses into the printed lens frame in sequence to obtain a semi-finished product; The semi-finished product is debugged and tested to obtain an industrial endoscope lens.

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